<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Document</title>
  </head>
  <body>
    <script>
      function Fun() {
        console.log(this);
      }
      var fun = new Fun();	// Fun中的this指向的是新创建的实例，即fun
    </script>
  </body>
</html>